Polypeptide liquid crystals

Uematsu, Ichitaro; Uematsu, Yoshiko

doi:10.1007/3-540-12818-2_6

Cited by 125 publications

(99 citation statements)

References 65 publications

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“…Such chemical modifications have already been shown to influence the formation of 3D liquid crystalline phases. [28][29][30][31][32][33] The interest in LMs of ␣-helical polypeptides also arises from the fact that many of them can be transferred onto solid substrates as multilayers using the Langmuir-Blodgett ͑LB͒ technique. In recent years, various ␣-helical poly͑L-glutamates͒ have been studied both as LMs on water 23,25,26,[34][35][36][37] and as LB films on solid substrates.…”

Section: Introductionmentioning

confidence: 99%

“…The lyotropic liquid crystalline behavior of conventional polydisperse PBLG in 3D has been known since the late 1950s; 28,[52][53][54][55][56][57][58][59] in particular, in addition to the usual cholesteric phase, 28,[52][53][54][55][56]58,59 the observations of nematic 53,54,60 and columnar 57 phases have been reported. Recently, Tirrell et al 61 demonstrated that unlike the polydisperse case, the monodisperse PBLG in both bulk solutions and solution cast films exhibits a smecticlike liquid crystalline order.…”

Section: Introductionmentioning

confidence: 99%

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Structure of poly(γ-benzyl-L-glutamate) monolayers at the gas–water interface: A Brewster angle microscopy and x-ray scattering study

Fukuto

Heilmann

Pershan

et al. 1999

The Journal of Chemical Physics

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. 1999. Structure of poly(\(\gamma\)-benzyl-L-glutamate) monolayers at the gas-water interface: A Brewster angle microscopy and x-ray scattering study. Journal of Chemical Physics 111 (21) This paper reports Brewster angle microscopy ͑BAM͒, x-ray specular reflectivity ͑XR͒, grazing incidence diffraction ͑GID͒ and off-specular diffuse scattering ͑XOSDS͒ measurements of Langmuir monolayers formed on water by both mono-and polydisperse samples of ␣-helical poly͑␥-benzyl L-glutamate͒ ͑PBLG͒ as a function of area/monomer A. The microscopic behavior does not exhibit any discernible effects due to differing dispersity. At low surface densities ͑A Ͼϳ21 Å 2 /monomer, surface pressure ⌸ϭ0͒, BAM images reveal partial surface coverage by solidlike monolayer islands. GID measurements show an interhelix peak corresponding to a local parallel alignment of rodlike PBLG molecules, indicating their tendency to aggregate laterally without external pressure. Compression to AϽ21 Å 2 /monomer first leads to full and uniform surface coverage by the monolayer, followed by a steep rise in ⌸ that is accompanied by a decrease in the interhelix distance. Further compression results in a plateau of constant ⌸ in the ⌸-A isotherm ͑ϳ11.5ϽAϽϳ18.5 Å 2 /monomer, ⌸ϳ9 dyn/cm͒, which has previously been attributed to a first-order monolayer-bilayer transition. The interfacial electron density profiles determined by the XR measurements on both sides of the coexistence plateau provide direct evidence for this transition. On the basis of x-ray scattering results, the film on the high-density side of the plateau is shown to consist of a newly formed incomplete and incommensurate second layer that sits on top of and has lower average density than a homogeneous first layer. GID measurements indicate that the second layer can be characterized by larger interhelix d-spacing than the first layer, while XOSDS measurements on the bilayer suggest that the second layer is microscopically inhomogeneous. For both mono-and bilayers, the analysis of observed GID peak widths indicates that the extent of lateral positional correlations between parallel PBLG rods ranges from a few to no more than ϳ15 interhelix distances, implying short-range order.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structure of poly(γ-benzyl-L-glutamate) monolayers at the gas–water interface: A Brewster angle microscopy and x-ray scattering study

Fukuto

Heilmann

Pershan

et al. 1999

The Journal of Chemical Physics

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“…However, it was not known what effect a change in the chiral nematic twist sense would have on this chiroptical activity since these derivatives formed only right-handed chiral nematic structures. It has been observed for lyotropic mesophases of poly(y-benzyl-L-glutamate)(PBLG) (22), and thermotropic mesophases of poly(ybenzyl L-glutamate-co-y-dodecyl L-glutamates) (23), that the CD for the phenyl side groups changes sign when a change in the chiral nematic twist sense occurs. The CD spectrum for the phenyl transitions in mesophases of THeC2 (solid line) and TPeCl (dashed line) in tetrahydrofuran at concentrations of 42 and 49 mass percent polymer, respectively, are shown in Fig.…”

Section: Chiroptical Propertiesmentioning

confidence: 99%

Left- and right-handed chiral nematic mesophase of (trityl)(alkyl)cellulose derivatives

Harkness¹,

Gray²

1990

Can. J. Chem.

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This paper is dedicated to Professor Arthur S. Perlin on the occasion of his 67th birthday BRIAN R. HARKNESS and DEREK G. GRAY. Can. J. Chem. 68, 1 135 (1990). A series of novel specifically substituted 6-0-trityl-2,3-0-alkyl cellulose derivatives have been prepared by the reaction of triphenylmethyl (trityl) cellulose in DMSO with powdered sodium hydroxide and an alkyl iodide (iodohexane, iodopentane, and iodobutane). These derivatives form lyotropic chiral nematic mesophases that exhibit both left-and right-handed twists. The dilute solution circular dichroism due to the phenyl chromophores along the chain does not correlate with the twist sense of the tertiary structures. However, a striking difference in the optical activity of the phenyl chromophores was observed in mesophases with the opposite twist sense. This may reflect some molecular factor responsible for the change in the macroscopic twist sense, or it may be due to the chirality of the helicoidal tertiary structure of the mesophase.Key words: cellulose, trityl, mesophase, cholesteric, chiroptical.BRIAN R. HARKNESS et DEREK G. GRAY. Can. J. Chem. 68, 1135 (1990). En faisant rCagir de la triphCnylmCthy1 (trityl) cellulose avec de l'hydroxyde de sodium et des iodures d'alkyles (iodohexane, iodopentane et iodobutane) en solution dans le DMSO, on a prepare une skrie de nouvelles 6-0-trityl-2,3-0-alkyl celluloses spCcIfiquernent substituCes. Ces dCrivCs foment des mesophases nematiques chirales lyotropes qui prCsentent des deviations vers la gauche ainsi que vers la droite. Des solutions diluees presentent un dichroi'sme circulaire qui est dii aux chromophores phCnyles de la chalne; il n'y a pas de correlation entre ces spectres et le sens de rotation des structures tertiaires. Toutefois, les mesophases de sens de rotation opposCs presentent des diffkrences remarquables dans I'activitC optique des chromophores phenyles. Cette diffkrence pourrait &tre le reflet de facteurs molCculaires responsables pour le changement dans le sens macroscopique de rotation ou bien elle pourrait &tre due a la chiralitk de la structure helicoidale tertiaire de la mesophase.

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“…[1][2][3] One of the applications of such liquid crystalline polymers was a gas or material-separation film. 4 We have prepared the cellulosic solid films retaining cholesteric liquid crystalline order (hereafter, CLCO solid films) [5][6][7][8][9][10][11] and determined the gas permeability in the ethyl cellulose (EC) solid films 12 ; the CLCO EC solid films exhibited better permselectivity of oxygen and nitrogen gasses, compared with that of amorphous EC solid films.…”

Section: Introductionmentioning

confidence: 99%

Gas transport phenomena in hydroxypropyl cellulose solid film retaining cholesteric liquid crystalline order

Suto

Kobayashi

1998

J. Appl. Polym. Sci.

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Two kinds of hydroxypropyl cellulose (HPC) films were prepared: one retained cholesteric liquid crystalline order (HPC-A), and another was amorphous (HPC-B). Gas transport phenomena in the HPC-A films were determined at 20°C, which is below the T g of HPC, compared with those in the HPC-B films, by using mainly oxygen and nitrogen gases; herium and carbon dioxide gases were also used. The permeability coefficient P for the HPC-A films was smaller than that for the HPC-B films by approximately 10 times. The gas permselectivity, defined as the ratio of P for each gas, was affected by the liquid crystalline order, as follows: The permselectivity for the HPC-A films was greater than that of the HPC-B films. The trends of gas permeability and permselectivity for the liquid crystal-forming HPC films were the same as those reported for other liquid crystal-forming cellulosic films.

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Polypeptide liquid crystals

Cited by 125 publications

References 65 publications

Structure of poly(γ-benzyl-L-glutamate) monolayers at the gas–water interface: A Brewster angle microscopy and x-ray scattering study

Structure of poly(γ-benzyl-L-glutamate) monolayers at the gas–water interface: A Brewster angle microscopy and x-ray scattering study

Left- and right-handed chiral nematic mesophase of (trityl)(alkyl)cellulose derivatives

Gas transport phenomena in hydroxypropyl cellulose solid film retaining cholesteric liquid crystalline order

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